Distribution of driving trajectory of passenger car in highway horizontal curves

In this paper the track behavior of passenger car was studied.The vehicle driving trajectory and driving direction were defined,and a classification of the type of vehicle trajectories along the curves was developed.The statistical parameters of vehicle trajectory samples in free flow and their frequency curves and cumulative frequency curves were achieved,K-S test and chi-square test were used to test normal distribution and gamma distribution for collected sample data,and the probability density functions were given.At last,dispersion degree between vehicle trajectory random variable and the characteristic value of cumulative frequency curve in each key cross section in curves was analyzied.The proposed conclusion can provide theoretical support for the reasonable optimization of widen curve,design of alignment and the management of counter flow conflicts.     

考虑客户价值的车辆调度干扰管理

针对物流企业中资源不能有效地分配到不同客户手中,难以实现物流企业经济效益最大化的问题,基于客户关系管理理论,在考虑客户价值的情况下,从客户、物流配送运营商以及物流配送员三方面对物流配送系统的扰动建立了车辆调度干扰管理模型,并结合免疫算法设计了改进的种子群优化算法对模型进行求解.结合具体实例,对考虑客户价值的干扰管理模型与未考虑客户价值的干扰管理模型进行比较,结果表明,考虑客户价值的干扰管理模型能够获得更大的客户满意度.     

基于ADAMS的滚筒平行度公差对输送带跑偏的影响*

应用机械系统动力学自动分析软件(ADAMS)建立带式输送机的虚拟样机模型,分析在不同驱动滚筒和从动滚筒平行度公差(d)下输送带的受力和偏移参数。结果表明:输送带的张力、法向接触力和轴向力影响输送带的偏移;d与输送带的受力呈单调递增关系,随着d增大,输送带单元的张力、法向接触力和轴向力提高,输送带的运行稳定性变差;d与输送带的偏移参数也呈单调递增关系,随着d增大,输送带单元的偏移速度、偏移加速度和偏移量增大,输送带跑偏严重;当d=0时,随着运行时间延长,输送带单元的偏移参数逐渐增大,输送带依然存在跑偏趋势;随着d减小,输送带跑偏的可能性降低,对输送精度要求较高的带式输送机应安装纠偏装置。     

基于m序列调制技术的叶绿素荧光检测系统设计

针对藻类叶绿素荧光信号微弱难以准确检测的问题,提出了基于m序列调制技术的叶绿素荧光检测系统。分析了荧光检测电路的噪声特点,设计了基于T型电阻反馈网络的I/V转换电路和二级放大电路;根据m序列解调原理,设计了双极性转换电路、移相电路和基于AD630的荧光信号解调电路。将系统应用于蛋白核小球藻叶绿素荧光检测,结果表明,对于叶绿素浓度为10 µg/L的蛋白核小球藻,测量相对标准偏差为2.61%。在0~100 µg/L叶绿素浓度范围内,检测系统输出直流电压值与蛋白核小球藻叶绿素浓度之间的线性相关系数达到0.998。     

信噪比对DIMM法测量大气相干长度的影响

在大气相干长度r0的测量中,相同的仪器和数据处理方法,不同的信噪比对实验测得结果有较大影响。通过分析实测中的噪声模型,利用matlab仿真,保持信号光强度不变,在光斑图像上添加高斯噪声,改变图像的信噪比。以不含背景时的光斑图像求得的r0作真值,分别求出不同信噪比下r0对真值的相对偏差。发现当信噪比小于5时,相对偏差大幅增加。在相同信噪比下,采用不同的背景处理方法,发现减去平均背景后,剩下的高斯噪声对质心位置的影响很小。在不同信噪比下,减1倍平均背景及0.6倍背景起伏标准差后相对偏差整体表现最小。     

种分槽顶液下泵的振动原因与对策

对改造中的种分槽顶液下泵的振动原因进行了分析,提出了改进的措施,实施后达到了预期效果。     

盾构施工中的隧道轴线纠偏判别算法

为控制盾构机沿隧道设计轴线前进 ,要把实际测量值与设计值进行比较 ,利用差值判别是否需要进行纠偏。隧道设计给出的设计图形为投影线形 ,本文经过推导给出了利用投影线形及求隧道设计轴线上任意点的空间坐标值及倾角的方法 ,进而进行纠偏判别     

基于球杆仪数控机床误差补偿方法研究

分析了基于球杆仪的数控机床误差补偿测试原理 ,讨论了由于角度偏差引起的误差 ,指出基于球杆仪误差补偿模型的缺陷 ,提出采用该种模型必须精确测量角度值     

Purposive Behavior Acquisition for a Real Robot by Vision-Based Reinforcement Learning

This paper presents a method of vision-based reinforcement learning by which a robot learns to shoot a ball into a goal. We discuss several issues in applying the reinforcement learning method to a real robot with vision sensor by which the robot can obtain information about the changes in an environment. First, we construct a state space in terms of size, position, and orientation of a ball and a goal in an image, and an action space is designed in terms of the action commands to be sent to the left and right motors of a mobile robot. This causes a state-action deviation problem in constructing the state and action spaces that reflect the outputs from physical sensors and actuators, respectively. To deal with this issue, an action set is constructed in a way that one action consists of a series of the same action primitive which is successively executed until the current state changes. Next, to speed up the learning time, a mechanism of Learning from Easy Missions (or LEM) is implemented. LEM reduces the learning time from exponential to almost linear order in the size of the state space. The results of computer simulations and real robot experiments are given.     

基于模型预测的VSC-MTDC协调控制策略

多端柔性直流输电(voltage source converter based multi-terminal direct current transmission, VSC-MTDC)系统主要应用于新能源发电并网和远距离输电。但由于新能源发电具有波动性和不确定性的特点,在使用传统下垂控制策略的情况下,VSC会因功率分配不均而过载、因直流电压偏差过大造成保护误动作、因通讯延时振荡。本文提出了一种基于模型预测控制(Model Predictive Control, MPC)的协调控制策略。该策略根据系统状态进行参数寻优,发送VSC功率基准,消除了下垂系数、线路电阻和系统拓扑对功率分配的影响。MPC的鲁棒性也提高了系统在通讯延时情况下的稳定性。在simulink中搭建了四端VSC-MTDC模型,并设置不同的运行条件进行时域仿真。仿真结果证明了该控制策略能够在系统发生扰动的情况下快速调节换流站功率和控制直流电压,并且在通讯延时发生时能保证系统稳定性,从而提高了电力系统对新能源发电波动性和不确定性的适应能力。